APIs have been around forever, but they historically have been complex, proprietary, difficult to use, and require tight coupling with a desktop application. Back when I first started writing commercial software, I used Btrieve (made by SoftCraft at the time) as my database engine and spent a lot of time messing around with the API to figure out how to make it work the way I wanted to. Of course, whenever I upgraded my programming environment, I had to wait for the API library upgrade, which never worked correctly with my legacy applications, which then caused me to waste even more time messing around with the API library.

One of the famous early PC APIs was the MS-DOS BIOS API. Quick – without looking – what did INT 19h do? By the time the Win32 API came along, I was done programming, but I hear it was a lot of fun to work with.

Today, virtually every popular web application has (or is rolling out) an API. Google, Yahoo, Amazon, and eBay have led the way, but newer web apps such as Flickr, EVDB, and del.icio.us are right there with them. Of course, in classic Internet fashion, each large company has their own name for them (web services anyone?) but API captures it for me.

As part of the NewsGator Online API release, NewsGator has created a sample application that uses their API. I’ve seen several posts recently about how “easy” it is to create an aggregator – we’ll – yeah – a simple one is easy. NewsGator has a sample 3–pane aggregator with full sync support that was created in a couple of hours. If you have a NewsGator Online account, give it a whirl – when you play with it, recognize that all the back end activity is done using the NewsGator Online system. FeedBurner has several good examples up, including the Podnova FeedBurner 40 top podcasts (by subscribers) and the number of subscribers on a each feed on Podfeed.net that uses FeedBurner.

Compared what you can do with the others – Google’s API is quite narrow. I wish I could access my personalized search history via an API – imagine being able to walk around with that data and having the capability of loading it into other search engines. APIs are fantastic – transparency is just one of important things that make Web 2.0 well, Web 2.0.

I've been test driving the Google Sidebar for a few days. It is interesting from the standpoint that it has a pluggable architecture with available API's (Brad thinks this is good :-)) The "out of the box" Sidebar items are…

I’ve been test driving the Google Sidebar for a few days. It is interesting from the standpoint that it has a pluggable architecture with available API’s (Brad thinks this is good :-)) The “out of the box” Sidebar items are…